ESD protection in a very small form factor consumer electronic product

ABSTRACT

A very small form factor consumer electronic product includes at least a single piece housing having an integral front and side walls that cooperate to form a cavity in cooperation with a front opening where an edge of the side walls define a rear opening and at least some of the edges have flanges. The consumer electronic product also includes an user input assembly having a size and shape in accordance with the front opening and a clip assembly having a size and shape in accordance with the rear opening and having an external user actionable clip, a plurality of internal hooking features, and a plurality of internal latching features. The clip assembly is secured by engaging at least some of the hooking features and the flanges on the edges of the housing and engaging the latching features and corresponding attachment features on the internal support plate.

CROSS REFERENCE TO RELATED APPLICATIONS

This U.S. patent application is a continuation of U.S. patentapplication Ser. No. 12/870,513, filed Aug. 27, 2010 entitled “ESDPROTECTION IN A VERY SMALL FORM FACTOR CONSUMER ELECTRONIC PRODUCT” byDabov et al., which is incorporated by reference in its entirety for allpurposes. This U.S. patent application is related to the following U.S.patents, each of which is incorporated by reference in their entiretyfor all purposes:

(i) “INHIBITING MOISTURE INTRUSION IN A VERY SMALL FORM FACTOR CONSUMERELECTRONIC PRODUCT” by Dabov et. al. filed Aug. 27, 2010 havingapplication Ser. No. 12/870,656, now U.S. Pat. No. 8,415,570; and

(ii) “VERY SMALL FORM FACTOR CONSUMER ELECTRONIC PRODUCT” by Dabov et.al. filed Aug. 27, 2010 having application Ser. No. 12/870,526, now U.S.Pat. No. 8,368,643.

BACKGROUND

1. Field of the Described Embodiments

The described embodiments relate generally to consumer electronicproducts and more particularly to very small media playback device thatis highly portable.

2. Description of the Related Art

In recent years, small form factor consumer electronic products such asmedia players and cellular phones have become smaller, lighter and yetmore capable by incorporating more powerful operating components intosmaller and more densely packed configurations. This reduction in sizeand increase in density can be attributed in part to the manufacturer'sability to fabricate various operational components such as processorsand memory devices in ever smaller sizes while increasing their powerand/or operating speed. However, this trend to smaller size and increasein component density and power, however, poses a number of continuingdesign and assembly challenges.

For example, small form factor consumer electronic products, such as amedia player, can require the assembly of a number of components into anenclosure having an extremely small volume. Assembling the variouscomponents into the housing having such a small size can requirecomplex, expensive, and time consuming assembly techniques. Moreover,aesthetic considerations can severely restrict the placement, size, andnumber of components used in the manufacture of the small form factorconsumer electronic product. For example, proper alignment of externalfeatures such as buttons can be extremely difficult to accomplish whenthe small size of the consumer electronic device itself can severelyreduce the available tolerance stack of the assembled components.

Another challenge to be dealt with concerns proper techniques formounting structures within the small form factor consumer electronicproduct. For example, using conventional assembly techniques, variousinternal components structures can be attached to housing fasteners suchas screws, bolts, rivets, etc and assembled in a sandwich like manner inlayer. However, using this technique with small form factor devices canbe time consuming, expensive, and prone to error.

In view of the foregoing, due at least to increase component density andreduced size there is a need for improved techniques for protectingagainst ESD in consumer electronic products.

SUMMARY OF THE DESCRIBED EMBODIMENTS

A media player includes a housing formed of an electrically conductivematerial and a button assembly that includes an external featurearranged to receive a user input event. The external feature isconnected to an internal switch displaced from the external feature byway of an electrically conductive arm that fits through a slit in amoisture flow inhibiting seal. The seal is formed of an insulatingmaterial and at least a portion of the seal is combined with aconductive dopant such that a conductive path is formed between theelectrically conductive arm and the housing. The conductive path allowsa quantity of charge deposited at the external feature to flow directlyto the housing by way of the electrically conductive arm and theconductive portion of the seal and bypass the internal switch.

In another embodiment, a media player includes a housing formed of anelectrically conductive material and a button assembly. The buttonassembly, in turn, includes an external feature arranged to receive auser input event, an electrically conductive arm arranged to connect theexternal feature to an internal switch and a metal base portionintegrally formed with the external feature. The metal base portionconnects the external feature to the electrically conductive arm and ametal label mounted to the metal base portion using a conductiveadhesive. A conductive path is formed between the electricallyconductive arm and the housing that allows a quantity of chargedeposited at the external feature to flow directly to the housing by wayof the metal label and the metal base portion and bypass the internalswitch.

A method can be performed by providing a housing formed of anelectrically conductive material, the housing having at least oneopening, providing a button assembly that includes an external featurearranged to receive a user input event, the external feature beingconnected to an internal switch displaced from the external feature byway of an electrically conductive arm, providing a block formed of anelectrically insulating and moisture resistant material having an slotsized to accommodate the electrically conductive arm, introducing aconductive dopant into at least a portion of the block such that theportion of the block is electrically conductive, inserting the externalfeature into the opening in the housing, and inserting the electricallyconductive arm into and through the slot in electrical contact with theconductive portion of the block. A conductive path is formed between theexternal feature and the housing by way of the electrically conductivearm and the conductive portion of the block, the conductive pathallowing a quantity of charge deposited at the external feature to flowdirectly to the housing and bypass the internal switch.

A method can be carried out by providing a housing formed of anelectrically conductive material and providing a button assembly thatincludes an external feature arranged to receive a user input event, anelectrically conductive arm arranged to connect the external feature toan internal switch, a metal base portion integrally formed with theexternal feature, the metal base portion connecting the external featureto the electrically conductive arm, and a metal label, and conductivelymounting the metal label to the metal base portion using a conductiveadhesive, wherein a conductive path is formed between the externalfeature and the housing by way of the metal label and the metal baseportion, the conductive path allowing a quantity of charge deposited atthe external feature to flow directly to the housing and bypass theinternal switch.

Other aspects and advantages will become apparent from the followingdetailed description taken in conjunction with the accompanying drawingswhich illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments will be readily understood by the following detaileddescription in conjunction with the accompanying drawings, wherein likereference numerals designate like structural elements, and in which:

FIG. 1 shows a front view of exemplary very small form factor mediaplayer in accordance with the described embodiments

FIG. 2 shows a side view of exemplary very small form factor mediaplayer of FIG. 1 with a clip in a closed configuration.

FIG. 3 shows a side view of exemplary very small form factor mediaplayer of FIG. 1 with a clip in an open configuration.

FIG. 4 is an exploded view showing various sub-assemblies of componentsused in the fabrication of media player 10.

FIGS. 5-7 show various perspective views of representative housing inaccordance with the described embodiments.

FIGS. 8-11 show various components of click wheel assembly in accordancewith the described embodiments.

FIG. 12 shows representative clip assembly in accordance with thedescribed embodiments.

FIG. 13 show representative click assembly seal in accordance with anembodiment.

FIG. 14 shows main logic board (MLB) assembly in accordance with anembodiment.

FIGS. 15-17 show perspective views of an audio jack assembly inaccordance with the described embodiments.

FIGS. 18-19 show interior moisture detection system in accordance withthe described embodiments.

FIG. 20 shows an assembly tool used to surface mount an audio jackassembly to a panelized printed circuit board in accordance with thedescribed embodiments.

FIGS. 21-24 show aspects of hold button assembly in accordance with thedescribed embodiments.

FIG. 25 shows a technique for reducing a tolerance stack of a playlistbutton to housing in accordance with an embodiment of the invention.

FIG. 26 shows a flowchart detailing an assembly process in accordancewith the described embodiments.

FIG. 27 shows a flowchart detailing a process for shunting anelectrostatic charge to a chassis ground in accordance with thedescribed embodiments.

FIG. 28 shows a representative media player in accordance with thedescribed embodiments.

DESCRIBED EMBODIMENTS

In the following paper, numerous specific details are set forth toprovide a thorough understanding of the concepts underlying thedescribed embodiments. It will be apparent, however, to one skilled inthe art that the described embodiments may be practiced without some orall of these specific details. In other instances, well known processsteps have not been described in detail in order to avoid unnecessarilyobscuring the underlying concepts.

This paper discusses an aesthetically pleasing portable computingdevice. The portable computing device can have a size and weightallowing the portable computing device to be easily carried about. Forthe remainder of this discussion and without loss of generality, theportable computing device will be discussed in terms of a very smallform factor media player arranged to store a plurality of digital mediaitems any of which can be selected and decoded for play. Due to thesmall size and light weight, however, any decoded media item signals(such as audio) are not broadcast by way of audio transducers such asspeakers. Rather than broadcast the audio signals as sound, the mediaplayer can utilize an interface such an audio jack to pass the decodedsignals to an external circuit for further processing. For example, whenthe decoded media file is an audio file, then the decoded audio signalcan be passed by way of an audio jack to an external circuit included inor attached to headphones, external speakers, audio recorder, and soforth.

The very small form factor media player can be sized for easy transportin a hand, a pocket, or attached to a lanyard and hung from a neck,wrist, waist, and so forth. Due in part to the small size and lack ofavailable space, the very small form factor media player can havelimited functionality. By limited functionality, it is meant that thevery small form factor media player can be targeted to perform specifictasks such as store, retrieve and decode a limited number of digitalfiles. Since additional processing of the decoded digital files islikely to be performed outboard of the very small form factor mediaplayer, input features used to control operations of the media playercan be limited to media file selection, media file decoding, and simpleoperational parameters such as volume increase/decrease. Therefore, thenumber and type of input features can be limited as well. For example,selecting of a stored media item (or items) can be performed by a usermanipulating a mechanical input along the lines of mechanical buttonsuch as a dome switch. The mechanical input can also be used to modifyother functions performed by the media player, such asincreasing/decreasing volume, fast forwarding/rewinding and so on. Insome cases, it can be advantageous to provide specific input featuresarranged to carry out specific functions. For example, an input featurein the form of a sliding switch can be used to activate a hold, orpause, function whereas a simple feature such as a button can be used toperform a complex operation such as select a playlist (group ofassociated media items).

The very small form factor media player can include a single piecehousing that is seamless in appearance formed of any number of durablematerials. In a particular embodiment, the housing can be formed of aconductive material suitable for providing good chassis ground. Thehousing can therefore be formed of materials such as metal, conductiveplastic or conductive composite material. One of the advantages to usingmetal for the housing is ability of metal to provide good electricalgrounding for any internal components requiring a good ground plane. Agood ground plane can be used to help mitigate the deleterious effectscaused by, for example, electromagnetic interference (EMI) and/orelectrostatic discharge (ESD). In a particularly useful configuration,the housing can be formed of from a single billet of metal such asaluminum. From the single billet of aluminum, the single piece housingcan be shaped and sized to accommodate a plurality of internalcomponents. Moreover, due to the single piece construction, variousopenings in the housing for accommodating various switches, connectors,and so on can be formed without the need to add additional structuralsupport. The aesthetic look and feel of the media player can besubstantially enhanced along with the long term resistance to corrosionand scratching by surface treating the aluminum. For example, anodizingthe aluminum housing can create a layer on the surface of the aluminumthat enhances the luster and sheen of the aluminum housing whilesimultaneously increasing the resistance to scratches and corrosion.

Simple and efficient design and assembly techniques can be used thatfacilitate both the aesthetic look and functionality of the very smallform factor media player. For example, due to the small size and closeproximity of the operational components within the media player, anyexternal moisture that finds its way into the interior of the mediaplayer substantially increases the likelihood of damage, either throughcorrosion or electrical shorts. Minimizing or at least hindering theintrusion of moisture into the interior of the media player can be animportant factor in the long term operability of the media player.Therefore, as part of the overall design, a number ofmoisture/contamination inhibitors can be strategically placed within themedia player. The inhibitors can take many forms, such as moistureresistant tape, adhesive, thermoformed plastic caps, and so forth. Theinhibitors can include, for example, water resistant membranes along theline of Kapton, Mylar and so forth. The inhibitors can also take theform of a block of compressible and moisture resistant material such assilicone rubber. In the described embodiment, the block shaped moistureinhibitor can have a portion removed to form a slit sized to accept amechanical arm used to activate a mechanical input such as a switch. Inthe described embodiment, the mechanical arm can pass through the slitformed in the moisture resistant material effectively isolating thatportion of the arm in contact with an active circuit and the exteriorportion exposed to the outside environment. In this way, the strategicplacement of moisture inhibitors can substantially reduce the risk ofmoisture entering the interior of the media player and causing corrosionand electrical shorts.

In addition to providing a good moisture inhibitor, in some embodiments,portions of selected moisture inhibitors can be enhanced in such a waythat a conduction pathway can be formed. For example, with regards tothe silicone rubber moisture inhibitor discussed above, the applicationof selected dopants (such as small silver spheres), the intrinsicinsulation properties of silicone rubber can be modified such that thesilicone rubber can become somewhat conductive to the point where a goodpath to ground can be formed. In this way, not only does the moistureinhibitor substantially hinder the passage of water into the interior ofthe media player, but also facilitates ESD protection by providing amechanism for dispersing accumulated charges to a ground plane in theform of the housing.

These and other embodiments are discussed below with reference to FIGS.1-xx. However, those skilled in the art will readily appreciate that thedetailed description given herein with respect to these figures is forexplanatory purposes only and should not be construed as limiting.

Turning first to FIGS. 1-3 showing representative very small form factormedia player 10 (hereinafter referred to more simply as media player 10)is shown various perspective views. Media player 10 can process data andmore particularly media data such as audio, video, images, and the like.By way of example, media player 10 can generally correspond to a devicethat can perform as a music player. Media player 10 can have operationalcomponents enclosed and supported by housing 12. Media player 10 canhave top portion 14, side portion 16, and bottom portion 18. Mediaplayer 10 can include one or more input devices. The one or more inputdevices can include a touch sensitive input device one of which can takethe form of a click wheel assembly mounted to a front portion of housing12 as shown in FIG. 1. The click wheel assembly can include at leastclick wheel 20. Click wheel 20 can be formed of resilient material suchas plastic or metal. Click wheel 20 can have a raised annular portion 22on which are presented a number of icons 24 each corresponding to aparticular button function that can be performed by media player 10 inresponse to a user touch event. The button functions can includeselecting and playing a song, fast forwarding or fast rewinding througha song, increasing/decreasing volume and the like. In the describedembodiments, the various button functions can be implemented via amechanical clicking action.

In order to convert the user touch event to a signal that can beprocessed and acted upon by media player 10, each icon 24 can beassociated with a sensor arrangement (described below). When pressure isapplied to a particular icon, the associated portion of click wheel 20can respond by mechanically engaging a corresponding one of a pluralityof sensors. In the simplest case, an electrical signal is produced eachtime a sensor is engaged. In most cases, the signals are monitored by anelectronic interface that converts the signal into information. Thisinformation can then be used by media player 10 to perform a desiredcontrol function. Click wheel 20 can also include center button 26.Center button 26 can be formed of plastic or metal. When pressure isapplied to center button 26, a signal can be generated that can causemedia player 10 to execute a pre-determined function. For example, whenpressure is applied to center button 26, a signal can be generated andforwarded to processing circuitry that can cause media player 10 tostart or stop the playing of a media item. It should be noted that theshape of click wheel 20 can also be widely varied. For example, clickwheel 20 can be circular, rectangular, square, oval, triangular, and thelike.

Bottom portion 18 can include clip assembly 28 that can have a closedconfiguration as shown in FIG. 2 and an open configuration as shown inFIG. 3. Clip assembly 28 can be used to secure media player 10 toexternal features such as clothing, lanyards and the like. Clip assembly28 can include clip 30 integrally formed with torsion spring block 32that includes a torsion spring, torsion spring block 32 being attachedclip plate 34 (also referred to as door 34). Clip plate 34 can includevarious attachment features (not shown), both hooking and latching typethat can be used to attach clip assembly 28 to housing 12 and fullyenclose the internal components of media player 10. In order to securelyattach media player 10 to an object using clip assembly 28, pressure Pcan be applied to clip 30 at about torsion block 32 causing clip 30 topivot away from clip plate 34 causing clip assembly 28 to transitionfrom the closed configuration of FIG. 2 to the open configuration ofFIG. 3. In this way, gap 36 can be formed between clip plate 34 and clip30 of sufficient size to accommodate an object or a portion of an objectsuch as a shirt sleeve, lapel, lanyard and so forth. Therefore, byremoving pressure P from being applied to clip 30, the spring forcecreated by the torsion spring in torsion spring block 32 can cause clip30 to engage the object when clip assembly 28 moves back to the closedconfiguration. In this way clip 30 can grasp and secure the objectwithout damage to either the object or media player 10 thereby easilysecuring media player 10 to objects such as clothing, lanyards and soforth.

Media player 10 can also include one or more switches such as playswitches, hold switches, and the like that are accessible throughvarious openings in housing 12. For example, hold switch button 38 canbe used to activate or deactivate click wheel 20. This is generally doneto prevent unwanted commands being generated by click wheel 20, as forexample, when media player 10 is stored inside a user's pocket. Holdswitch button 38 can take many forms such as a two, three or moreposition button. For example, when configured as a three position switchas shown in FIGS. 2 and 3, hold switch button 38 can have a first,second and third position relative to housing 12. In order to providethe user with a quick and unambiguous indication of the position of holdswitch button 38, label 40 can be provided. Label 40 can providedistinctive visual indicia (such as different colored portions as shownin FIGS. 2 and 3 in the form of green portion GP and blue portion BP) toindicate the position of hold switch button 38. For example, in positiontwo (corresponding to a central positioning of hold switch button 38),label 40 can unambiguously indicate that hold switch button 38 has beenplaced in position two by concurrently presenting both green portion GPand blue portion BP of label 40. In order to remain clear and distinctover an expected operating life of media player 10, label 40 can beformed of resilient material such as metal.

Media player 10 can include audio jack port 42. Audio jack port 42 canmechanically and electrically couple media player 10 to an externalcircuit whereby audio information can be outputted from media player 10and data imported to media player 10. In some cases, power can also betransferred to media player 10 by way of circuitry associated with audiojack port 42. Audio jack port 42 can receive a post (not shown) that canfacilitate the transfer of information (or power) between media player10 and external circuits. For example, audio signals from decodeddigital audio files can be passed to external audio rendering devices,such as headphones, speakers, etc. In order to minimize the number andcomplexity of mechanical input assemblies required to operate mediaplayer 10, a number of multi-function mechanical inputs can be provided.For example, playlist button 44 can be used to activate a complexfunction such as selecting a playlist of media items for play by mediaplayer 10. As well known in the art, the playlist is a collection ofmedia items such as songs that have been chosen to be played one at atime as a group. Therefore, any songs identified as belonging to aparticular playlist can be selected, decoded, and played by simplydepressing playlist button 44. In this way, any need for complex userinteraction, such as scrolling can be eliminated thereby rendering mediaplayer 10 simple in design and easy to operate.

FIG. 4 is an exploded view showing various sub-assemblies of componentsused in the fabrication of media player 10. The sub-assemblies caninclude housing 100, click wheel assembly 200; clip assembly 300, mainlogic board (MLB) assembly 400, and hold switch assembly 500 eachdescribed in more detail below.

A first perspective view of an embodiment of housing 12 shown in FIG. 5as housing 100 can be formed of any number of materials such as plasticor metal which can be forged, molded, or otherwise processed into adesired shape. In those cases where media player 10 has a metal housingand incorporates RF based functionality, it may be advantageous toprovide at least a portion of housing 100 in the form of radio (or RF)transparent materials such as ceramic, or plastic. In any case, housing100 can be configured to at least partially enclose any suitable numberof internal components associated with media player 10. Housing 100 canenclose and support internally various structural and electricalcomponents (including integrated circuit chips and other circuitry) toprovide computing operations for media player 10. The integratedcircuits can take the form of chips, chip sets, modules any of which canbe surface mounted to a printed circuit board, or PCB, or other supportstructure.

Housing 100 is thus effectively a chassis or “exoskeleton” for theoverall device that contains the device components and can also serve asa starting point for assembling the entire device. Housing 100 can alsoinclude various openings some of which can be used to install an insertcontaining various internal components, as well as buttons, ports, anaudio jack, and the like, as set forth below. For example, front opening102 can be sized to receive click wheel assembly 200 whereas rearopening 104 can accommodate clip assembly 300. Opening 106 (shown moreclearly in FIGS. 6 and 7 each of which provide second and thirdperspective views, respectively, of housing 100) can be sized to acceptaudio jack port 42 whereas opening 108 can accept playlist button 44while opening 110 can accept hold switch button 38. Securing features112 can be used to assist in securing internal components to housing 12using a fastener such as a screw. Flanges 114 can support a moistureinhibiting seal arranged to at least inhibit the intrusion of moistureinto the interior of media player 10.

When housing 100 is formed of a good conductor, such as aluminum,housing 100 can function as a chassis ground that provides a good groundplane for internal electrical components. In addition to providing agood ground plane for internal electrical components, the metallicnature of housing 100 can help prevent static electrical charge fromaccumulating thereby reducing the possibility of an electrostaticdischarge damaging sensitive electrical components. However, in order toimprove the aesthetic look of housing 100, a substantiallynon-conductive surface layer can be formed on housing 100. This surfacelayer can provide excellent corrosion and scratch protection but cannonetheless prevent good electrical contact to the underlying metal. Forexample, in the case where housing 100 is formed of aluminum, ananodizing process can cause a layer to form on the surface of housing100 (both interior and exterior surfaces). This layer can prevent a goodelectrical contact to the underlying base aluminum severely degradingthe ability of housing 100 to provide a chassis ground. A goodelectrical contact to the underlying aluminum base layer can be achievedby selectively removing at least portion 116 of the protective layerfrom interior surface 118 of housing 100 as shown in FIG. 7.

FIGS. 8 through 11 show the components and the relationship between thecomponents of click wheel assembly 200. It should be noted that clickwheel assembly 200 is self contained in that once fully assembled, clickwheel assembly 200 is fully functional and capable of being functiontested prior to incorporation into media player 10. Turning first toFIG. 8 click wheel assembly 200 can include button ring assembly 202.Button ring assembly 202 can include click wheel 20 (described above)and membrane 204 that can be attached to an inside portion of clickwheel 20 by way of adhesive. Shown in more detail in FIG. 9, membrane204 can be formed of a resilient material such as silicone rubber.Membrane 204 can be sized to fully accommodate click wheel 20. Forexample, click wheel 20 can be placed entirely within and on membrane204 in such a way that raised perimeter portion 206 of membrane 204 canengage outer edge 208 of click wheel 20 forming a tight seal betweenclick wheel 20 and membrane 204 when top surface 210 of membrane 204 isattached to click wheel 20 using, for example, adhesive. In this way,button ring assembly 202 to can be considered a single sealedsub-assembly. Prior to membrane 204 being attached to click wheel 20,shims 212 can be placed within recesses 214 associated with each icon 24in annular region 22 and center button 26 of click wheel 20. Shims 212can be used to adjust the mechanical response of click wheel 20 to atouch event by a user. Shims 212 can adjust a distance by which clickwheel 20 moves in response to the touch event at a particular one oficons 24 or center button 26. In this way, the subjective feel clickwheel 20 can be modified as needed.

FIG. 10 shows representative button plate 218 in accordance with thedescribed embodiments. Surface 216 of membrane 204 can be used to securebutton ring assembly 202 to button plate 218. Button plate 218 can beformed of strong and resilient material such as metal or any suitablecomposite material. In the embodiments described herein, however, buttonplate 202 will be considered to be formed of metal without loss ofgenerality. Accordingly, metal button plate 218 can be formed of metalssuch as stainless steel and aluminum. Metal button plate 218 can beattached to button ring assembly 202 by attaching surface 216 ofmembrane 204 to surface 220 of metal button plate 218 using any suitableadhesive such as dual sided adhesive tape. Surface 220 of metal buttonplate 218 can include sensors 222 associated with a corresponding one oficons 24 and 26. As described above, when pressure is applied to clickwheel 20 in proximity to icons 24 or 26, the corresponding sensor 222can respond to the applied pressure by generating a signal that can beused by control circuitry to modify operations of media player 10.

In the described embodiment, sensors 222 can take the form of mechanicalswitches such as dome buttons 222 (also referred to as tact switch,short for tactile switch). The number of placement of dome buttons 222can be widely varied. For example, anti-rotation ring 224 can be placedin such a way as to prevent rotation of click wheel 20 surrounding domebutton 222 associated with central button 26. In the particularembodiment shown, dome buttons 222 form an array of five switchesconnected to click wheel flex 226 each of which align with an associatedone of icons 24 and 26 on click wheel 20. Click wheel flex 226 caninclude connector flex 228 that can be used to electrically connectclick wheel assembly 200 to operational circuits within media player 10.In particular, connector flex 228 can be connected to a main logicboard, or MLB, using a zero insertion force (ZIF) connection describedand shown below.

Metal button plate 218 can include metal boss 230 welded to downwardfacing surface 234. Metal boss 230 can be used to attach metal buttonplate 218 (along with click wheel assembly 200) to internal componentssuch as a printed circuit board, or PCB. Tabs 232 can be used to secureclick wheel assembly 200 to clip assembly 300 during an assemblyoperation. For example, clip assembly 200 can be latched to metal buttonplate 218 using tabs 232. In this way, button metal plate 218 can beconsidered dual use in that surface 220 of metal button plate 218 can beused to support button ring assembly 202 whereas surface 234 shown inFIG. 11 can be used to support components such as a printed circuitboard by way of welded metal boss 230 and clip assembly 300 by way oftabs 232. Connector 236 can be used to electrically connect flexconnector 228 to electrical components such as the MLB. Moreover,openings 238 align with openings 112 formed in housing 100. In this way,a fastener can be used to secure at least metal button plate 234directly to housing 100.

FIG. 12 shows an embodiment of clip assembly 300. Clip assembly 300 canbe pre-assembled and tested prior to being used to complete assembly ofmedia player 10. Clip assembly 300 can be pre-assembled using fasteners302. Fasteners 302 can take the form of screws 302. Screws 302 can beused to mount clip door 34 to torsion block 32 that houses torsionspring 304. Torsion spring 304 can keep clip 30 in tension against clipdoor 34 in the closed configuration. Clip assembly 300 can be attachedto metal button plate 218 by way of hooking features 306 that engagewith tabs 232 on metal button plate 218. Attachment feature 308 can takethe form of a hook that can engage opening 240 formed in metal buttonplate 218.

As shown in FIG. 13, seal 310 can be formed of moisture inhibitingmaterial such as silicone rubber. Seal 310 can be shaped to conform toopening 106 of housing 100 in proximity to flanges 114 formed withopening 106. Seal 310 can be placed on housing 100 in proximity toflanges 306. In this way, seal 310 can inhibit the intrusion of moistureor other liquids from the external environment to an interior portion ofhousing 100. This is particularly important due to the presence ofvarious openings within housing 100 each of which presents a potentialmoisture intrusion pathway.

Seal 310 can be sized and shaped in accordance with housing 100 and inparticular opening 106. Seal 310 can be shaped to inhibit moistureintrusion into the interior of housing 100 and in particular thoseportions of housing 100 that have openings for input devices such asbuttons or switches that are exposed to the external environment. Forexample, opening 312 in seal 310 can correspond to a battery used toprovide power to media player 10. Opening 314 can on the other handcorrespond to a main logic board, or MLB, juxtaposed to the battery.Since the MLB includes a number of electrical components that are likelyto be moisture intolerant, portion 314 can be configured to provide amore robust barrier to the intrusion of moisture than that provided byportion 312.

During assembly of media player 10, seal 310 can be placed directly ontoflanges 114 of housing 100. Once in place, clip assembly 300 can bedirectly placed on seal 310 and pressure applied to clip assembly 300.The pressure applied to clip assembly 310 can cause hooks 306 to engagetabs 224 of metal button plate 218 and attachment feature 308 to engageopening 240. In this way, click wheel assembly 200 and clip assembly 300can be securely attached to each other in such a way to minimize theintrusion of moisture to the interior of media player 10. By foregoingthe requirements to use fasteners such as screws to mount clip assembly300 to housing 100, there are no visible fasteners providing mediaplayer 10 with a clean and efficient appearance.

Due to the small size and compact nature of media player 10, the effectsof moisture intruding into media player 10 can have seriousconsequences. For example, due in part to the high packing density ofinternal components within media player 10, even a small amount ofmoisture can cause a leakage path between components resulting inreduced functionality or even damage. This is especially true sincethere is little unused space within media player 10 resulting in a muchhigher probability of moisture induced damage. In addition to damagepotentially caused by moisture intrusion, damage from electrostaticdischarge, or ESD, can be severe. Again, due to the small size and tightgeometries, electric fields strength can become so high thatconsiderable voltage spikes are possible. This is particularly true whenconsidering the close proximity of sensitive components in the MLB andexternal switches such as playlist button 44 and hold button 38. A usermerely engaging a switch or even just picking up media player 10 couldeasily be responsible for an electrostatic discharge having thepotential for electrically damaging any number of sensitive electricalcomponents. Accordingly, ESD protection and the inhibition ofmoisture/contamination intrusion are important considerations in thedesign and layout of media player 10.

FIG. 14 shows main logic board (MLB) assembly 400 in accordance with anembodiment. MLB assembly 400 can include MLB 402. MLB 402 can includeprinted circuit board (PCB) 404 onto which are mounted and electricallyconnected a plurality of integrated circuits 406. The integratedcircuits can include at least a microprocessor, semi-conductor (such asFLASH) memory, various support circuits and so on. Power can be suppliedto the integrated circuits by battery 408 connected to PCB 404 by way ofelectrical connectors 410. Battery 408 can be a lithium ion typebattery. Playlist tact switch 412 and “side firing” hold tact switch 414are also shown. It should be noted that the term “side firing” is meantto convey the idea that due in part to layout considerations andcomponent density, hold switch 38 can be displaced from the position ofhold tact switch 414. In this way, an armature (described in more detailbelow) can connect hold switch 38 and hold tact switch 414. Connector416 can connect to flex connector 228 at contacts 236. In oneembodiment, connector 416 can be a zero insertion force, or ZIF,connector well known in the arts. Opening 418 can align with weldedmetal boss 230 and be sized to accept a fastener such as a screw thatcan be used to secure MLB assembly 400 to click wheel assembly 200. Inthis way, the fastener can securely join MLB assembly 400 and clickwheel assembly 200.

MLB 402 can include audio jack assembly 420 that can be surface mountedonto PCB 404 by way of audio jack body 422. Audio jack assembly 420 caninclude audio jack barrel 424 integrally formed with audio jack body 422each being suitably sized and positioned on PCB 404 to align withopening 106 in housing 100. In this way audio jack barrel 424 canreceive an audio jack post by way of audio jack port 42, the audio jackpost having electrical contacts that align with and electrically connectwith an exposed portion of audio jack contacts 426 described and shownin more detail in FIGS. 15 and 16. More specifically, FIG. 15 shows aside view of audio jack assembly 420 illustrating the relative positionof audio jack contacts 426 with respect to audio jack barrel 424, audiojack body 422, and PCB 404. In the described embodiments, audio jackcontacts 426 can include portion 427 embedded within audio jack body422. However, in order to make good electrical contact withcorresponding electrical contacts on an audio jack post that is insertedinto audio jack port 42 a portion of audio jack contacts 426 can beexposed to interior 428 of audio jack barrel 424 as audio jack pads 430.

It should be noted that interior volume 428 can be directly exposed tothe external environment, an environment that can include substantialamounts of contaminants and moisture. Therefore any path betweeninterior volume 428 and the interior of media player 10 that couldpotentially allow the passage of the contaminants and moisture must becarefully considered. Accordingly, path 432 can be considered to be apotential flow path between contact post 434 placed through PCB opening436 used to connect audio jack pads 430 to circuitry 438 surface mountedto PCB 404.

In order to prevent, or at least minimize the potential for theintrusion of contaminants and moisture from interior volume 428, amoisture inhibitor can be used to severely restrict if not entirely stopany direct flow of contaminants and/or moisture along path 432. Themoisture inhibitor can include more than a one component. For example,in order to restrict or eliminate the possibility of passage of moistureor contaminants to the interior of media player 10 along path 432, anumber of moisture flow inhibitors can be incorporated within path 432.In one embodiment, PCB opening 436 can be filled with solder during asurface mounting procedure used to electrically connect post 434 toelectrical traces on PCB 404. As part of a standard assembly procedure,PCB 404 can undergo a wave solder process whereby solder is flowed overthe surface of PCB 404. The flow of solder can fill in PCB opening 436by way of a wicking action. The wicking action can have the effect ofsealing any gaps that may exist at an interface of PCB 404 and connectpost 434 as well as between audio jack body 422 and connect post 434.

In place of or in addition to the solder, other moisture inhibitors thatcan be incorporated into path 432 can include at least layer 440. Layer440 can be formed of material well suited to inhibit the flow ofmoisture or contaminants. Layer 440 can, for example, take the form of athin film or tape such as Kapton and Mylar that can conform to theexternal shape of audio jack barrel 424 and audio jack body 422. Forexample, moisture flow inhibiting film 440 can be placed in directcontact with audio jack body 422 and audio jack barrel 424 extending toa region that covers contact holder area 442 shown in more detail inFIG. 16. In some cases, adhesive material may be required to assure thatfilm 440 substantially conforms to the shape of audio jack barrel 424and audio jack body 422. For example, an adhesive layer can be placed ontop of film 440 forcing film 440 to conform to the surface features ofaudio jack barrel 424 and audio jack body 422. Placing adhesive on topof film 440 can be particularly advantageous when film 440 is thin andlikely to wrinkle. Any gaps between film 440 and audio jack body 422 andaudio jack barrel 424 can themselves present additional pathways formoisture/contaminant intrusion in the interior of media player 10. Inorder to assure full compliance and maximize the inhibition of the flowof moisture and contaminants into the interior of media player 10,contact post 434 can pass through film 440 further inhibiting the flowof moisture/contaminants between interior 428 and the interior of mediaplayer 10.

In another embodiment, the moisture flow inhibitor can take the form ofstructures such as cap 444 that can be mounted directly to audio jackassembly 420 as shown in FIG. 17. Cap 444 can be formed of moistureresistant material that can be formed by a thermoforming process to havea shape that conforms to that of audio jack assembly 420. In particular,cap 444 can include openings sized and placed to accommodate contactpost 434 and mounting posts 446 used to attach audio jack assembly 420to PCB 404. In some cases, it may be advantageous to secure cap 444 toaudio jack assembly 420 using adhesive. Cap 444 can be placed andsecured during the assembly process. Since cap 444 has been shaped toconform to the contours of audio jack assembly 420, the likelihood ofgaps between cap 444 and audio jack body 422 and audio jack barrel 412can be practically eliminated. In this way, any anti-wrinklingprocedures needed when film 440 is used are not necessary with the useof cap 444.

In order to monitor whether or not the interior of media player 10 hasbeen exposed to moisture, a number of moisture indicators can be placedwithin the interior of media player 10. One of the most common moistureindicators provides a visual indication, generally by changing colors(e.g., from white to red) when moisture comes into contact with it. Thevisual indication can be viewed through a viewing port structure. Inthis way, any moisture intrusion can be readily identified. Due to thedirect exposure of audio jack interior 428 to the external environment,there is a possibility that moisture within audio jack interior 428 canintrude into the interior of media player 10 if not by path 432 but byother moisture intrusion paths. Therefore, determining the path that anymoisture within interior of media player 10 took from the externalenvironment can represent significant data both for design purposes aswell as customer service and relations. Any abusive behavior can havethe effect of rendering any manufacturer warranty invalid. For example,if there is an indication that moisture has penetrated the interior ofmedia player 10, then a reasonable conclusion is that media player 10was exposed to an environment having a high concentration of moisturesuch as a lake, pool, or stream. In this way, a warranty condition mayhave been violated having the possibility of an uncovered repairexpense.

Therefore, a moisture detection system can be provided to determine ifmoisture has intruded into the interior of media player 10. It should benoted, however, that it is expected and anticipated that moisture willbe present at audio jack interior 428. Therefore, the moisture detectionsystem described herein must distinguish between the expected presenceof moisture within audio jack interior 418 and moisture that haspenetrated into the interior of media player 10.

FIG. 18 illustrates moisture detection system 450 in accordance with thedescribed embodiments. Moisture detection system 450 can be locatedwithin the interior of media player 10. Moisture detection system 450can provide a visual indication, generally by changing colors (e.g.,from white to red) when moisture comes into contact with a moisturedetecting layer indicating that moisture has penetrated into theinterior of media player 10. Moisture detection system 450 can beconnected to viewing port 452 located at end 454 of audio jack barrel422 by an adhesive layer (not shown). The adhesive layer can be of anysuitable adhesive material such as two-sided pressure sensitive adhesivefilm (double sided tape), an adhesive without film backing etc. Moisturedetection system 450 can include frame 456 connected to viewing portstructure 452.

Moisture detection system 450 can include a number of layers such aswicking layer 458 and dyeing layer 460. Wicking layer 458 can be made ofa wicking material that can provide a capillary action or the ability todraw another substance, in this case moisture, into it. Wicking layer458 can have a pre-specified color when dry and no foreign substance hasbeen wicked into it. For example, wicking layer 458 can have an“unwicked” color that is typically white but could also be gray, a lightcolor, etc. In order to accentuate the change in color when exposed tomoisture, ink layer 462 can be provided that partially obscures wickinglayer 458. Ink layer 462 can be colored to contrast with the “wicked”color of wicking layer 458 in order to provide a better viewingexperience especially when viewing through the small opening representedby audio jack port 42. For example, if the “unwicked” color of wickinglayer 458 is white, then ink layer 462 can be a matching white such thatwhen, and if, wicking layer 458 changes color, that change in color willcontrast with the unchanged color of ink layer 462 making the colorchange even more readily apparent even through the small openingrepresented by audio jack port 38.

In the described embodiment, dyeing layer 460 can be placed adjacent towicking layer 458. Dyeing layer 460 can be made of a dry dye, or coloredsubstance, of a predefined color, typically red. When dyeing layer 460is in dry form, wicking layer 458 has no wicking ability so that the tworemain separated. Once dyeing layer 460 becomes moist or wet, the drydye becomes wet and is wicked into wicking layer 458. In this way,wicking layer 458 can become viewable through viewing port 452 having ashape influenced by ink layer 462 where the dye has a color thatcontrasts with that of ink layer 462. When there has been no moistureinfiltration of the dry dye, wicking layer 458 appears to have a drycolor, such as white, through viewing port 452 as no wicking hasoccurred. However, when moisture infiltrates the dry dye, the dye, nowwet, wicks into and through wicking layer 458 such that the color of thedye that passes into wicking layer 458 is apparent through viewing port452. Once the dye has been wicked into wicking layer 458, the dye willremain even after wicking layer 458 dries.

FIG. 19 shows an external view of moisture detection system 450.

In order to facilitate the placement of audio jack assembly 420 onto PCB404, assembly tool 470 can be used to support and align audio jackassembly 420 onto PCB 404. Accordingly, FIG. 20 shows panel 472 formedof a plurality of PCBs connected together by way of tabs 474. As wellknown in the art, printed circuit boards are generally fabricated inlarge numbers in the form of a sheet, or panel, of printed circuitboards bound together by panel tabs. After all appropriate circuits andassemblies have been mounted to the panelized PCB, the integratedcircuits and assemblies can be electrically connected to traces in thePCB using any number of connection processes such as soldering using,for example, a wave soldering process. However, prior to the connectingprocess, audio jack assembly 420 can be placed upon PCB 404 withoutsubstantial support. In this way, there is a possibility of audio jackassembly moving or otherwise becoming mis-aligned either before orduring the soldering process.

Accordingly, assembly tool 470 can be used to place and temporarilysecure audio jack assembly 420 to each of the PCBs in PCB panel 472.Assembly tool 470 can take the form of a post that can be placed withinport 48 having a length such that the post can extends completelythrough audio jack barrel 422 (also referred to as “spearing”). In thisway assembly tool 470 can be supported by tab structure 478 and PCB 404.In this way, assembly tool 470 can support each of the panelized PCBs.In this way, audio jack assembly 420 can be surface mounted to thecorresponding one of the panelized PCBs while supported by assembly tool460. After audio jack assembly 420 has been successfully surfacemounted, assembly tool 470 can be removed and discarded.

Turning now to FIGS. 21 and 22, hold switch assembly 500 in accordancewith the described embodiments is shown in more detail. Hold switchassembly 500 can include hold switch carrier 502. Hold switch carrier502 can be formed of any suitable resilient material such as plastic. Inorder to minimize the intrusion of moisture from the externalenvironment through hold switch carrier 502, hold switch carrier seal504 can be placed on hold switch carrier 502. Hold switch carrier seal504 can be formed of moisture inhibiting material such as siliconerubber. In this way hold switch carrier seal 504 can have a shape thatsnug fits within hold switch carrier 502. Moreover, hold switch carrierseal 504 can have a number of openings that allow passage of mechanicalactuators. For example, playlist button 44 can be accommodated byopening 506 in hold switch carrier seal 504. However, in order tominimize the likelihood of moisture entering the interior of mediaplayer 10, playlist button plunger 508 that extends from playlist button44 to playlist tact switch 412 can pass through hold switch carrier seal504 through opening 2810 in such a way that effectively seals playlistbutton plunger 508 leaving little or no room for moisture to pass fromthe external environment to the interior of media player 10.

In order to further reduce the likelihood of moisture gaining access tothe interior of media player 10, hold switch arm 512 attached to holdswitch button 38 on one end and hold switch side firing tact switch 414on the other end can pass through slit 514 formed in hold switch sealblock 516. Hold switch block seal 516 can be formed of resilientmaterial such as silicone rubber and can be tightly fitted in carrier502. Pressure applied to block seal 516 can compress the silicone rubberabout that portion of arm 512 in slot 514 with substantially affectingthe movement of arm 514. In this way, any moisture present at holdbutton 38 can be prevented from entering the interior of media player10.

It should be noted that in some cases it can be advantageous from an ESDmitigation standpoint to dope the silicone rubber of block seal 516 withconductive material such as silver spheres 518 shown in FIG. 23.Conduction path 520 from hold switch 38 to chassis ground at housing 100by way of arm 512 can be provided. In this way, any electric charge ator near hold switch 38 can be conducted to chassis ground in the form ofhousing 100. It should be noted, however, that in order to provide agood electrical contact point at housing 100, portion of the surfacelayer (if any) of housing 100 must be removed in order to expose themetallic substrate. For example, in the case of housing 100 being formedof anodized aluminum, laser etching portion 522 of housing 100 canprovide a good electrical contact for doped and therefore electricallyconductive seal 516.

FIG. 24 shows another embodiment of hold switch assembly 500 in whichconduction path 524 can be provided between hold switch button 38 andhousing 100. Metallic label 40 can be attached to hold switch arm 512using conductive adhesive along the lines of solder forming conductivelayer 526 between label 40 and hold switch arm 512. In this way, chargeon hold switch button 38 can be directed along conduction path 524 tohousing 100. However, in order to assure a good electrical contactbetween hold switch arm 512 and housing 100, portion 114 of housing 100can be abraded to expose the underlying metal substrate, which in thisexample is aluminum. In one embodiment, the surface layer associatedwith portion 114 can be removed using a laser to etch an appropriateamount of the surface layer from portion 114. In this way, hold switcharm 512 moves such that label 38 comes in direct contact with theunderlying metal layer of housing 100 at laser etched portion 114.

It should be noted that in addition to providing a good electricalcontact point, by exposing the softer aluminum under layer of housing100 to metal label 38 at portion 114, wear and tear on label 38 issubstantially reduced. For example, when the aluminum of housing 100 isanodized, the surface layer formed is very hard to the point that label38, even when formed of stainless steel, can be scratched or otherwisedamaged by the repeated sliding against the surface layer of theanodized aluminum of housing 100. However, when laser etched, the nativealuminum under layer of housing 100 exposed in portion 114 does notappreciably damage or otherwise mar label 38.

Due to the very small size of media player 10, it can be difficult andtime consuming to properly align external features, such as playlistbutton 44 to housing 100. FIG. 25 shows a particularly useful alignmenttechnique used to install and align playlist button 44 (or any otherexternal feature) in accordance with the described embodiments. Inparticular, FIG. 25 shows PCB 404 on which at least a portion of tabs478 remain. Playlist button 44 can include plunger 508 that can pressupon on playlist tact switch 412. In order to minimize the tolerancestack between playlist button 44 and housing 100, tabs 478 can be lasercut at laser cut line 2502 as opposed to fiducials 2504 on PCB 404. Inthis way, the tolerance stack can be greatly reduced substantiallyimproving the look and feel of playlist button 42.

FIG. 26 shows a flowchart detailing assembly process 2600 in accordancewith the described embodiments. Assembly process 2600 can begin at 2602by providing housing. The housing can be formed of metal or any otherappropriate material. The housing can also include a number of openingssized and placed to accommodate the insertion and assembly of variousinternal components. In the described embodiment, the housing includesat least a front opening suitably sized to accommodate a click wheelassembly and a rear opening suitable sized to accept a clip assembly. Inany case, the media player is assembled using what is referred to as aninside-out assembly technique described in more detail below. Once thehousing has been provided, a fully assembled and functionally testedinput device that can take the form of a click wheel assembly can beprovided at 2604. The click wheel assembly can include a front facingclick wheel having a number of input features that can be activated by auser. For example, the input features can take the form of clickableswitches that can react to a user press event by engaging a actuatorarranged to generate a signal in accordance with the press event. Theclick wheel assembly can also include a dual purpose metal plate havingan outward facing surface having the actuators for generating the signaland an inwardly facing surface having an attachment feature used tosecure internal components such as a main logic board assembly, or MLB.At 2606, a fully assembled and functionally tested MLB can be provided.The MLB can include a number of integrated circuits, switches, and I/Odevices. The switches can include at least a direct firing playlistbutton tact switch and a side firing hold button tact switch laterallydisplaced from an external hold button. The MLB can also include asurface mounted audio jack assembly and a battery.

At 2608 the MLB assembly and the click wheel assembly can beelectrically connected to each other by way of a flex connector from theclick wheel assembly to a zero insertion force, or ZIF, electricalconnector at the MLB assembly. At 2610, the MLB assembly and the clickwheel assembly are mechanically coupled to each other. In the describedembodiment, the boss on the inwardly facing surface of the metal plateof the click wheel assembly accepts a fastener such as a screw. Thescrew is used to mechanically secure the MLB assembly to the click wheelassembly. Next at 2612, the click wheel assembly/MLB assembly isinserted into the rear opening of the housing and aligned with the frontopening of the housing. The playlist button and the hold button arealigned with corresponding openings in the housing as is the audio jackunit. At 2614, a door seal is placed on an outer edge of the rearopening. The door seal is formed of resilient material such as siliconerubber and inhibits the flow of moisture/contaminants from the externalenvironment to an inside of the media player.

Next at 2616, the clip assembly is inserted into the rear opening and at2618 the clip assembly is snap connected to the housing flanges on thehousing at about the same time as the clip assembly is latch connectedto latching features on the click wheel assembly at 2620.

FIG. 27 shows a flowchart detail process 2700 for providing ESDprotection in portable device in accordance with the describedembodiments. Process 2700 can be used to shunt an electrostatic chargedeposited on a hold button to a chassis ground, which in this example isthe housing. Process 2700 can be carried out by providing a hold buttonseal formed of a material that is substantially electrically insulatingat 2702. In the described embodiment, the hold button seal can be formedof resilient material such as silicone rubber. In general the materialsused to form the hold button seal are generally insulating in nature inthat they generally do not facilitate a charge flow. At 2704, at least aportion of the hold button material is rendered electrically conductive.In the described embodiment, the changing of at least the portion of thehold button seal from insulating to conduction can be achieved by dopingthe portion of the hold button material with conducting dopant materialsuch as silver micro-spheres. At 2706, the doped hold button seal isused to enclose a hold button arm that mechanically links an externalhold button to an internal hold button switch. At 2708, the conductiveportion of the hold button seal is placed in electrical contact withchassis ground. In the described embodiment, the chassis ground can takethe form of an electrically conductive housing formed of, for example,aluminum. Next at 2710, any electrostatic charge deposited on theexternal hold button is shunted away from the internal hold buttonswitch to the chassis ground.

FIG. 28 is a block diagram of media player 2800 in accordance with thedescribed embodiments. Media player 2800 includes processor 2802 thatpertains to a microprocessor or controller for controlling the overalloperation of media player 2800. Media player 2800 stores media datapertaining to media items in a file system 2804 and a cache 2806. Thefile system 2804 is, typically, a storage disk or a plurality of disks.The file system typically provides high capacity storage capability formedia player 2800. However, since the access time to the file system2804 is relatively slow, media player 2800 also includes a cache 2806.The cache 2806 is, for example, Random-Access Memory (RAM) provided bysemiconductor memory. The relative access time to the cache 2806 issubstantially shorter than for the file system 2804. However, the cache2806 does not have the large storage capacity of the file system 2804.

Further, the file system 2804, when active, consumes more power thandoes the cache 2806. The power consumption is particularly importantwhen the media player 2800 is a portable media player that is powered bya battery (not shown).

Media player 2800 also includes a user input device 2808 that allows auser of media player 2800 to interact with media player 2800. Forexample, the user input device 2808 can take a variety of forms, such asa button, keypad, dial, etc. Still further, the media player 2800includes data bus 2810 can facilitate data transfer between at least thefile system 2804, the cache 2806, the processor 2802, and the CODEC2812.

In one embodiment, media player 2800 serves to store a plurality ofmedia items (e.g., songs) in the file system 2804. When a user desiresto have the media player play a particular media item, a list ofavailable media items is displayed on the display 2810. Then, using theuser input device 2808, a user can select one of the available mediaitems. The processor 502, upon receiving a selection of a particularmedia item, supplies the media data (e.g., audio file) for theparticular media item to a coder/decoder (CODEC) 2812. The CODEC 2812then produces audio output signals for audio jack 2814 to output to anexternal circuit. For example, headphones or earphones that connect tomedia player 2800 would be considered an example of the externalcircuit.

In another embodiment, a computer-readable medium is provided thatincludes computer program instructions for performing the various stepsof assembly described in FIG. 26. Specifically, the computer programinstruction may act to control various automatic installationcomponents, such as, for example, robotic arms, automatic screwdrivers,etc. That can assembly the device without the need for humanintervention (or, at least, minimizing human intervention). In this way,the computer instructions may be programmed to control a machine toinsert various components into the housing without substantial humanintervention. The computer instructions can also be programmed tocontrol a machine to perform laser etching and laser routing in additionto any other process required for the assembly and testing of the mediaplayer.

The various aspects, embodiments, implementations or features of thedescribed embodiments can be used separately or in any combination.Various aspects of the described embodiments can be implemented bysoftware, hardware or a combination of hardware and software. Thedescribed embodiments can also be embodied as computer readable code ona computer readable medium for controlling manufacturing operations oras computer readable code on a computer readable medium for controllinga manufacturing line. The computer readable medium is any data storagedevice that can store data which can thereafter be read by a computersystem. Examples of the computer readable medium include read-onlymemory, random-access memory, CD-ROMs, DVDs, magnetic tape, and opticaldata storage devices. The computer readable medium can also bedistributed over network-coupled computer systems so that the computerreadable code is stored and executed in a distributed fashion.

The foregoing description, for purposes of explanation, used specificnomenclature to provide a thorough understanding of the describedembodiments. However, it will be apparent to one skilled in the art thatthe specific details are not required in order to practice theinvention. Thus, the foregoing descriptions of specific embodiments arepresented for purposes of illustration and description. They are notintended to be exhaustive or to limit the invention to the precise formsdisclosed. It will be apparent to one of ordinary skill in the art thatmany modifications and variations are possible in view of the aboveteachings.

What is claimed is:
 1. A portable electronic device, comprising: ahousing formed from electrically conductive material; a moisture flowinhibiting seal comprising an electrically conductive pathway in contactwith the electrically conductive material of the housing; and anexternal feature configured to receive a user input, the externalfeature being connected to an internal switch displaced from theexternal feature by way of an electrically conductive arm that fitsthrough the moisture flow inhibiting seal, wherein a grounding pathwayis formed between the electrically conductive arm, the electricallyconductive pathway of the moisture flow inhibiting seal and theelectrically conductive material of the housing, the grounding pathwayallowing a quantity of charge deposited at the external feature to flowdirectly to the electrically conductive material of the housing, therebybypassing the internal switch.
 2. The portable electronic device asrecited in claim 1, wherein the housing provides a chassis ground andhas a cavity sized to enclose a plurality of operational components atleast some of which are susceptible to damage when exposed to anelectrostatic discharge (ESD) event.
 3. The portable electronic deviceas recited in claim 1, wherein the electrically conductive pathway ofthe moisture flow inhibiting seal is formed by adding a conductivedopant to at least a portion of the moisture flow inhibiting seal. 4.The portable electronic device as recited in claim 1, wherein thehousing comprises an internal anodized surface, at least a portion ofwhich is substantially removed to allow contact between the electricallyconductive material of the housing and the moisture flow inhibitingseal.
 5. The portable electronic device as recited in claim 1, whereinthe external feature comprises a slide switch.
 6. The portableelectronic device as recited in claim 1, wherein the electricallyconductive pathway of the moisture flow inhibiting seal comprises aplurality of conductive particles embedded within the moisture flowinhibiting seal.
 7. The portable electronic device as recited in claim1, wherein the electrically conductive material is aluminum.
 8. Theportable electronic device as recited in claim 1, wherein theelectrically conductive material of the housing is substantially coveredby an oxide layer and wherein the oxide layer over a surface portion ofthe housing in contact with the moisture flow inhibiting seal isremoved.
 9. The portable electronic device as recited in claim 8,wherein the oxide layer is removed by a laser etching process.
 10. Theportable electronic device as recited in claim 8, wherein the oxidelayer is an anodized layer comprising aluminum oxide.
 11. A mediaplayer, comprising: a housing having an electrically conductive surfacedisposed on an inside surface of the housing; and a user interface,comprising: an external feature extending through an opening in thehousing and arranged to receive a user input event, and an electricallyconductive member arranged to couple the external feature to an internalswitch by way of a metal base portion; and a metal label conductivelymounted to the metal base portion by a conductive adhesive such that aconductive pathway is formed between the external feature and a portionof the electrically conductive surface of the housing by way of themetal label and the metal base portion, the conductive pathway allowinga quantity of charge deposited at the external feature to flow directlyto the electrically conductive surface of the housing, thereby bypassingthe internal switch.
 12. The media player as recited in claim 11,wherein the user interface comprises a switch assembly.
 13. The mediaplayer as recited in claim 12, wherein the metal label is configured todisplay a color indicative of an operating mode of the media player whenthe media player is in at least one of a plurality of modes.
 14. Themedia player as recited in claim 11, wherein the electrically conductivesurface is aluminum.
 15. The media player as recited in claim 11,wherein the conductive adhesive is solder.
 16. A method, comprising:mounting a moisture resistant seal to an electrically conductive insidesurface of a housing, the moisture resistant seal comprising anelectrically conductive pathway and a slit, wherein the electricallyconductive pathway is in contact with both the slit and a conductivesurface of the housing; and installing a user interface assembly withinthe housing such that the user interface assembly is disposed through anopening in the housing and through the slit in the moisture resistantseal, wherein a first end of the user interface assembly comprises anexternal feature configured to receive a user input event and a secondend of the user interface assembly comprises an electrically conductivearm coupled with an internal switch within the housing, wherein agrounding path is formed between the external feature and the conductivesurface of the housing by way of the electrically conductive arm and theelectrically conductive pathway of the moisture resistant seal, theelectrically conductive pathway allowing a quantity of charge depositedat the external feature to flow directly to the conductive surface ofthe housing, thereby bypassing the internal switch.
 17. The method asrecited in claim 16, further comprising: laser etching a portion of anoxide layer covering the electrically conductive inside surface.
 18. Themethod as recited in claim 16, wherein the housing comprises aluminumsubstantially encased in an oxide layer.
 19. The method as recited inclaim 16, wherein the moisture resistant seal further comprises rubberinfused with metallic particles, the metallic particles forming theelectrically conductive pathway.
 20. The method as recited in claim 16,wherein the user interface assembly is a button assembly and theexternal feature is a slide switch.